For nanocarriers with low protein affinity, we show that the interaction of nanocarriers with cells is mainly affected by the density, the molecular weight, and the conformation of polyethylene glycol (PEG) chains bound to the nanocarrier surface. We achieve a reduction of nonspecific uptake of ovalbumin nanocarriers by dendritic cells using densely packed PEG chains with a “brush” conformation instead of the collapsed “mushroom” conformation. We also control to a minor extent the dysopsonin adsorption by tailoring the conformation of attached PEG on the nanocarriers. The brush conformation of PEG leads to a stealth behavior of the nanocarriers with inhibited uptake by phagocytic cells, which is a prerequisite for successful in vivo translation of nanomedicine to achieve long blood circulation and targeted delivery. We can clearly correlate the brush conformation of PEG with inhibited phagocytic uptake of the nanocarriers. This study shows that, in addition to the surface’s chemistry, the conformation of polymers controls cellular interactions of the nanocarriers.

Fungal infections remain a threat due to the lack of broad spectrum fungal vaccines and protective antigens. Recent studies showed that attenuated Blastomyces dermatitidis confers protection via T cell recognition of an unknown, but conserved antigen. Using transgenic CD4+ T cells recognizing this antigen, we identify an amino acid determinant within the chaperone calnexin that is conserved across diverse fungal ascomycetes. Calnexin, typically an ER protein, also localizes to the surface of yeast, hyphae and spores. T cell epitope mapping unveiled a 13-residue sequence conserved across Ascomycota. Infection with divergent ascomycetes including dimorphic fungi, opportunistic molds, and the agent causing white nose syndrome in bats induces expansion of calnexin-specific CD4+ T cells. Vaccine delivery of calnexin in glucan particles induces fungal antigen-specific CD4+ T cell expansion and resistance to lethal challenge with multiple fungal pathogens. Thus, the immunogeneticity and conservation of calnexin make this fungal protein a promising vaccine target.

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Chromoblastomycosis is a chronic skin infection caused by the pigmented saprophytic mould Fonsecaea pedrosoi. Chronicity of infection can be broken by a coordinated innate recognition of the spores by pattern recognition receptors. While Mincle signaling via theKeywords: Chromoblastomycosis r C-type lectin r Fungi r Dectin-2 r Mincle r T-cell differentiation r Th17 cell Additional supporting information may be found in the online version of this article at the publisher's web-site IntroductionChromoblastomycosis is a chronic progressive fungal infection of mammalian skin and subcutaneous tissue that is caused by which gradually enlarge and become verrucous nodules and psoriasis like plaques that may extend as satellites along the lymphatics or disseminate through scratching [5]. Chromoblastomycosis treatment is difficult and most therapeutic attempts provide only a modest rate of success [6,7].Little is known about the protective host defense mechanisms against chromoblastomycosis. Innate immunity mediated by neutrophils and macrophages is thought to be principally responsible for host protection [2,3]. However, the chronic nature of infection with F. pedrosoi may be due to an inappropriate innate immune response [8]. F. pedrosoi is recognized by the C-type lectin receptors (CLRs) Dectin-1 and Mincle, yet fails to induce the production of proinflammatory TNF-α by macrophages and DCs. Inflammatory responses to F. pedrosoi and clearance of infection can be reinstated by exogenous TLR costimulation [8]. Imiquimod (TLR7 ligand) and LPS (TLR4 ligand) application augments TNF-α production and accelerates healing in murine models [8] TLR costimulation does not augment Ag-specific T-cell development in F. pedrosoi-infected miceWe have previously shown that F. pedrosoi spores alone failed to induce innate inflammatory responses by macrophages. The failure of innate recognition could be reinstated by TLR costimulation [8]. To explore whether Ag-specific T-cell responses can be augmented by TLR costimulation we injected F. pedrosoi spore-infected mice with LPS as described [8]. Surprisingly, LPS (TLR4 agonist) and Imiquimod (TLR7 agonist) treatment did not increase the activation (CD44), expansion, and differentiation of Ag-specific 1807 cells as indicated by the numbers and frequencies of activated (CD44 + ) and cytokine producing (IFN-γ and IL-17) 1807 cells (Fig. 1A-E). Thus, unlike innate inflammatory responses, the generation of adaptive cell-mediated immune responses could not be augmented by costimulation of the TLR pathway. sought to investigate whether surface expressed CLRs are involved in the innate recognition of the fungal spores. We cocultured live F. pedrosoi spores with CLR transformed B3Z T-cell hybridoma cells expressing an NFAT-lacZ β-galatosidase reporter of ITAM signaling [15]. In response to spore stimulation, lacZ activity was increased in reporter cells expressing Dectin-1 and Dectin-2 and to a lesser extent MCL (Dectin-3, Clecsf8, or Clec4d) and Mincle, but not in cells expressing FcRγ only (Fig....